Air-cooled brake structure for centrifugal separators



Dec. M), 11935. H. J. PRETTO 2,024Jl3 AIR COOLED BRAKE STRUCTURE FOR CENTRIFUGAL SEPARATORS Filed Jan. 21, 1935 2 Sheets-Sheet l D@ w, i935. H g, PRETTO www AIR COOLED BRAKE STRUCTURE FOR CENTRIFUGAL SEPARATORS Filed Jan. 2l, 1955 2 Sheets-Sheet 2 Patented Dec. 1Q, 1935 ATNT @FICE AER-COOLED BRAKE STRUCTURE FOR CENTRIFUGAL SEPRATORS Application January 21, 1933, Serial No. 652,796

4 Claims.

This invention relates to centrifugal separators and similar machines and is more especially concerned with mechanisms for driving machines of this type.

It has been customary heretofore to arrange centrifugals in a battery or row and to drive them from a single shaft. A common arrangement is to use a battery of vertical or suspended centrifugal separators in connection with mixing, grinding, or similar machines, and to drive the entire series of centrifugals from a horizontal shaft through quarter turn belts and friction pulleys or equivalent clutch mechanisms .so arranged that each machine can be shut down independently of the others. More recently it has been found advantageous, however, to change over these drives to an individual motor drive for each machine or unit. The present invention deals with this problem and aims to facilitate the making of such change-overs and to devise a simple, reliable, and economical drive.

A centrifugal separator of the suspended type usually includes a brake mechanism arranged to act on the driving pulley or on a brake drum which forms an extension o-f said pulley. In shutting down the machine with the aid of such a brake mechanism considerable heat necessarily is developed at the driving pulley and the proper dissipation of this heat has proved to be a troublesome factor. 1t is, therefore, a further object of this invention to devise a driving mechanism in which objectionable heating of the drum will be substantially avoided.

The nature of the invention will be readily understood from the following description when read in connection with the accompanying drawings, and the novel features will be particularly pointed out in the appended claims.

In the drawings,

Figure l is a side elevation of a centrifugal separator equipped with a driving mechanism embodying features of this invention;

Fig. 2 is a perspective view of one element of the mechanism shown in Fig. 1;

Fig. 3 is a vertical, sectional view through the upper part of the driving mechanism for the machine; and

Fig. 4 is a plan View of the driven pulley and the parts immediately associated therewith.

Referring first to Figs. l, 3, and 4, the arrangement there shown comprises a centrifugal separator 2 of the suspended type associated with a mixer, or similar machine, the bottom of which is indicated at 3 in Fig. 1. The separator is of the Well known Weston type and includes a (Cl. 18S- 264) the rapid rotation of the quill around the rela- 10 tively stationary supporting shaft Associated with the drum E is an internal expanding brake, best shown in Fig. 4, which includes two brake shoes 9 and lll, both pivoted on the pin l2, the opposite ends of the brake 1 5.y

shoes being connected by toggle links I3 and l, Fig. fl, to an operating plunger l5 which, in turn, is pivoted at I6 to a handle or lever ll. Normally ie toggle l3-l4 is held in a broken or collapsed condition, but when the lever Il is swung 20 upwardly, this movement is transmitted to the toggle mechanism and tends to straighten it, thus operating to force the brake shoes 9 and l away from each other and into Contact with the inner surface of the brake drum 6. This serves to stop g5 the rotation of the shaft 5 and the basket 4.

All of the mechanism so far described is substantially like that heretofore used, the drum 6 serving both as a driven pulley on which the driving belt runs and also as a brake drum co- 30 operating with the brake mechanism above described.

In order to facilitate the changing over of the driving mechanism to an individual motor drive, a bracket I8, Fig, l, is Supported adjacent 35 to the drum 6 in any convenient manner where it will form a support for the electric motor 2). In the particular arrangement shown a leg 2| which is bolted to the bottom of the mixer trough 3 is secured to one end of the bracket while the opposite end is connected by one or more upright supports 22 to the adjacent frame beam or beams. On this bracket is mounted a platform or motor base 23 for supporting the 45 motor in a vertical position with its shaft projecting downwardly below the platform, suitable bolts, one of which is shown at 24, being inserted loosely through a portion of the bracket and threaded into the base 23 for adjusting the 50 motor horizontally toward and from the drum 6. This motor may be belt connected in any suitable manner to the upper end of the driving shaft 5. Preferably, however, a series of V-belts 25 are used for this purpose and accordingly, a 55 grooved pulley 26 is secured to the lower end of a motor shaft 2l.

In order to accommodate belts of this type and at the same time to obviate the diiiiculties heretofore experienced due to excessive heating of the drum 6, a pulley 23 of novel form is installed on the drum. This pulley, as clearly shown in the drawings, is of a generally cylindrical form and consists of a sleeve which is provided with a series of external or peripheral grooves to receive the belt 25. At its opposite ends it has lugs 3U which are drilled t0 receive bolts 3| by means of which it is fastened securely but removably to Athe drum 6. It is also provided internally with a series of spiral ribs 32, preferably extending.

from one end to the other of the sleeve, and preferably, also, arranged to bear at their inner edges against the peripheral surface of the drum.

Due to the fact that the drum 6 is not customarily crowned but is provided with a cylindrical outer surface, the pulley 28 can be slipped over the drum 6 after the latter has been drilled and tapped to receive the bolts 3| and can be secured to the drum Without further machine work. The installation of the bracket I8 and the motor 20 is a relatively simple matter so that all of the operations involved in properly mounting the parts and connecting the pulleys 26 and 23 can be performed with the expenditure of relatively little time and labor.

It should be noted that due to the presence of the spiral ribs 32, the main body of the pulley Y is spaced from the drum 6, and that when the machine is in operation the inclination of the ribs 32 will create a continuous flow or circulation of air through the air space between the drum 6 and the pulley 28. Such a construction is useful in retarding the transmission of heat from the drum to the pulley and also in cooling both the drum and the pulley, dissipating the heat created by the action of the brake mechanisin, and maintaining better operating, conditions at the driving surface of the grooved pulley 28. 'I'he invention thus represents a substantial improvement in the driving mechanisms for centrifugal separators and similar machines.

While I have herein shown and described a typical embodiment of my invention, it will be understood that the invention may be embodied in other forms without departing from the spirit or scope thereof.

Having thus described my invention, what I desire to claim as new is:

1. In a machine of the character described, the combination with a shaft and a brake drum mounted thereon, of a pulley encircling said drum and secured thereto, the brake drum constituting the sole support for the pulley, said pulley having inclined ribs on its inner surface to bear against said drum and space the main body of the pulley from the drum, said ribs terminating on the upper edge of the pulley in apertured lugs to receive bolts for securing the 10 pulley to the drum, said ribs serving also to create a current of air through the space so provided.

2. A pulley sleeve constructed to encircle and to be secured to a drum and provided on its inner surface with a plurality of inclined ribs serving to space the main body of the sleeve from said drum andto act on the air between the drum and sleeve to create a circulation oi' said air, said ribs terminating on the upper edge of the pulley sleeve in apertured lugs to receive bolts for securing said sleeve to said drum, said apertured lugs being inset with reference to the peripheral surface of the sleeve to prevent the y heads of the bolts securing the sleeve to the 20 drum from projecting beyond said peripheral surface.

8. In a machine of the character described, the combination with a shaft and a brake drum mounted thereon, of a pulley encircling said drum and secured thereto, the brake drum constituting the sole support for the pulley, said pulley having inclined ribs on its inner surface to bear against said drum and space the main body of the pulley from the drum, and apertured lugs at opposite ends of the pulley to receive bolts for securing the pulley to the drum, said ribs serving also to create a current of air through the space so provided.

4. A pulley sleeve constructed to encircle and 49 be secured to a drum and provided on its inner surface with a plurality of inclined ribs serving Y to space the main body of the sleeve from said drum and to act on the air between the drum and sleeve to create a circulation of said air, and apertured lugs at opposite ends of the sleeve to receive bolts for securing the sleeve to the drum, said apertured lugs being inset with reference to the peripheral surface of the sleeve to prevent the heads of the bolts securing 5o the sleeve to the drum from projecting beyond said peripheral surface.

HENRY J. PRET'I'O. 

